The primary objective of this paper is to assess the affect of data 'censoring' on asset pricing tests. This is achieved by modifying tests to incorporate a 'selectivity bias' correction factor in a Gibbons (Journal of Financial Economics, 10, pp. 3-27, 1982) multivariate framework. The sample comprises daily Australian stock returns for 524 companies over the five-year period 1995 to 1999. First, it is found that the use of a 'selectivity bias' correction factor is generally justified in stocks with a degree of censoring at about 50% or above. This represents approximately 52% of the sample. Second, despite the first finding no evidence is found supporting the need for such a correction in asset pricing tests - the degree of support for the CAPM is not materially affected.